rms? what happens if its 275, and i only got 150 for it?

orthaeeoul · #1 03-09-2008, 08:30 PM

Hi all, i searched for this, but couldnt find anything on it, so here i go.
i have invested in a pioneer 4 channel 600w amplifier, great sound, cant complain, anyway, its currently running 2 5 way pioneer 6"/9"'s, sounds very good, but only 150w is going to each, (not the issue)
i also have a sub box, 2 12" subs, each has a rms(?) of 275w.
how will it sound if i run 150W to each subwoofer?
what i dont know, if what effect (sound quality, bass loudness, bass strength, etc) will it have? cause im stumped...

1991_Vn2nV · #2 03-09-2008, 09:12 PM

That shouldn't cause a problem.

However, those 6x9's are only 80wrms mate, so you are basically running twice as much power into them as you should be.

orthaeeoul · #3 03-09-2008, 11:18 PM

true... but they dont distort at all, iv had it up to max volume on the deck, and zero distortion. so im not complaining...

1991_Vn2nV · #4 04-09-2008, 01:03 AM

Its probably just hard to tell the distortion from the noise created by the speakers lol (I used to have a set of the Pioneer 5 ways).

Its your choice, but its really not a good idea because you will stuff them eventually.

1991_Vn2nV · #5 04-09-2008, 01:14 AM

Actually I just checked the specs on that amp and at 4ohm its only 60wrmsx4. So it'd be fine to run the speakers off of it, but not really suitable for the subs.

StoneX · #6 04-09-2008, 05:52 AM

Quote:

Originally Posted by 1991_Vn2nV

Actually I just checked the specs on that amp and at 4ohm its only 60wrmsx4. So it'd be fine to run the speakers off of it, but not really suitable for the subs.

Lucky you checked! I was about to post up the real power ratings

If the subs are 275Wrms each, you should use an amp that will make about 500-600Wrms but you need to find out the impedance of the subs. Like 4 ohm, 2 ohm, etc.

holdenboy · #7 04-09-2008, 06:54 PM

Yes you always want (if possible) to run MORE power into your speakers / subwoofers than what they are rated at. Remember almost all power ratings are taken at 14.4v, and with a fixed ohm load.

When you turn up speaker/s, the voice coil heats up and the impedance rises.....so a 4 ohm speaker can easily jump alot higher than that, reducing the power from the amplifier.
Also, if you start your car and put a multimeter on the battery you'll notice it will be around 13.5-14.4v. If you turn the stereo up, put the headlights on etc the voltage will drop.

Say you have an amplifier that produces 60wrms at 4 ohm on 14.4v. That would be reduced alot if the impedance doubles and the voltage drops to 13.0v. The said amp may be only putting out 30 or 40wrms.

So it really pays to buy an amplifier with as much power as possible, as a general rule i would buy an amplifier with 1.5x the power of your chosen speakers / subwoofers. Also, it is FAR more common occurance to blow speakers by underpowering them, as opposed to overpowering them.

Back on topic, i personally would leave the speakers running off that Pioneer amplifier and invest in a monoblock amplifier for your subwoofers, i would imagine those subwoofers are single 4 ohm voice coils....so wiring them together (both +s and -s joined together) would give you an impedance of 2 ohms. i would go to your local or trusted car audio store and enquire about a monoblock that produces between 500 and 800wrms at 2 ohm, preferably more if you can afford it.
Also, you'll need another run of power cable....4AWG power/ground cables will do the job fine, and if you head-unit has sub RCA preouts you'll need another RCA cable to run from the head-unit to the monoblock. If it dosent you'll need to run RCAs from the outputs of the 4ch. amplifier and into the monoblock.

Any questions, just ask or pm me.....ive been a car audio installer for over 10 years and presently run my own car audio / security business.

orthaeeoul · #8 04-09-2008, 09:03 PM

sorry guys, i forgot to post specs...
the subs are in a ported box, with them each having there own sections, (sealed), the subs are GT5-12 JBL's..
The amplifier is a pioneer GM-6300F 4 channel.
and the deck is a DEH-5950IB pioneer.
so ur saying i should get a bigger amp? any ideas for under $400?

Phreddy · #9 05-09-2008, 01:08 PM

I'd suggest a monoblock of some description. Run the two JBLs in parallel (I assume they're 4 ohm per speaker, the parallel connection will give your amp a load of 2 ohms, which any decent monoblock is quite happy to drive into) Look at something which can do up around 600W into 2 ohms, that should match pretty well. Use the other two channels of the Pioneer amp to drive some front splits when you can afford them - that will make your system sound MUCH better, bringing the "sound stage" more in front of you.

Jaycar do a "Response" monoblock amp, retails at $399 - pushes 600WRMS into 2 ohms (1000W into 1 ohm) - quite a respectable brand, good value for money.

Hope it helps. Cheerz!